VacTran 3 Manual, страница 6

In somebusiness environments such privileges are managed by system administrators or PC support groups.3) If you would prefer to manually install the key rather than reinstall the whole program from the CD, go to thedirectory called© 2011 Professional Engineering ComputationsInstallation23“c:/Program Files/Common Files/PEC/USB Key Installer”Run “setup.exe”. This must be done with full administrative privileges for the driver to be installed properly.4) If the key is working properly after installation, it is possible to get the key recognition error if the computer hasbeen put into sleep or hibernate mode. The current version of the driver software from SafeNet Incorporatedsometime does not reinitialize the connection with the key after the system "wakes up". If this happens,simply exit VacTran and restart.

If the key is still not recognized, you may have to physically unplug the keyfrom your PC and reinsert it for Windows to recognize it, then restart VacTran. The important lesson here is tosave your work before putting the system to sleep or into hibernate mode.5) VacTran usually installs the most recent software drive for the key.

The most update to date driver can bedownloaded directly from SafeNet at http://www.safenet-inc.com/support/tech/sentinel.asp6) Notify PEC immediately if the hardware key is defective. Return it to PEC in its original static free packageusing registered US mail, UPS, FedEx, or another traceable delivery service.© 2011 Professional Engineering Computations243VacTran 3IntroductionVacTran facilitates the execution of laborious vacuum calculations, enabling rapidcharacterization and evaluation of vacuum system operational data and design alternatives.As the use of vacuum technology has become common in manufacturing and research, more people with a varietyof backgrounds are involved in designing vacuum systems. Rigorous calculations of performance are oftendisregarded in favor of rules of thumb.

Let’s face it: it’s not that difficult to bolt up any pump (that fits) to a vessel.Why bother with calculations when it’s easy enough to put together a system and start pumping?Why do calculations? The reasons are simple.Pump down time can affect operational costs, mission readiness, and customer satisfaction.A well-designed pumping system affects the quality of the productPump capacity is often wasted due to low efficiency piping.Better performing systems are more competitive in the marketplace.High-risk systems have to perform to specification the first time.In an increasingly competitive economic environment, inefficiency is no longer acceptable in many market sectors.Whether optimizing the production throughput of a coating system load lock or evacuating an accelerator ring ofsuper conducting magnets, efficient and predictable design is a necessity.VacTran can significantly reduce the calculation time and effort for designing vacuum systems, or for diagnosingproblems in existing systems.

Familiarity with vacuum system technology and reasonable design procedures isessential to make effective use of the program, since modeling and results interpretation are only as valid as theassumptions made by the user. Several references are listed in the bibliography for further study. The AmericanVacuum Society (www.avs.org), with chapter organizations around the country, offers many high quality shortcourses on vacuum technology.

Local community colleges are another source of training.VacTran was designed to ease the process of modeling a vacuum system. It was developed to solve common, realproblems in industry and national labs. All suggestions for program improvement are gratefully acknowledged.See also:What does VacTran do?How is VacTran organized?When are the different types of models used?Where are the models’ dependencies?Some models can generate othersFor starters, what’s important to remember?New features in version 33.1What does VacTran do?VacTran willCalculate the pump down time of a vacuum system, with and without gas loadsModel conductance elements such as pipes and elbows, and determine their effect on the delivered speedof the systemModel raw data conductance elements representing conductance vs.

pressure© 2011 Professional Engineering ComputationsIntroduction25Calculate the rate of pressure rise for a vacuum vessel based on its gas load.Model vacuum pumps and raw data gas loads with full editing features, including a pump curve digitizerutilityModel surface outgassing, permeations, and leaks, and calculate the rate of rise for a vacuum vesselGraph a multitude of vacuum system calculations with flexible plotting parameters that are easily changedCreate professional-looking graphs that can be used in publications or presentations or saved in standardgraphics formats.From the beginning, VacTran has never used proprietary formulas in performing its calculations.

All equations arefrom published sources, so the user can manually check results with hand calculations. Calculated datacontinuously updates a live text window, which can be examined or saved at any time.Industrial vacuum engineers have used VacTran worldwide for over twenty years. We only usecommon methods that are widely accepted in the vacuum industry. Although VacTran is notintended to solve every system application, it is designed to provide enough general utility to beuseful for a wide variety of problems.see alsoWhat does VacTran do?How is VacTran organized?When are the different types of models used?Where are the models’ dependencies?Some models can generate othersFor starters, what’s important to remember?New features in version 3© 2011 Professional Engineering Computations263.2VacTran 3How is VacTran organized?VacTran is organized into models, libraries, studies, and viewers.ModelsA model is a representation of a vacuum system or a component of a system.System model:Pump model:Raw data gas load:Raw data conductance:Series conductance ModelParallel conductance modelPump StationGas Model:A complete vacuum system, with gas loads, piping, and pumpsSpeed vs.

pressure data representing a pumpGas load vs. time data representing a complete gas evolution from a material overtimeConductance vs. pressure dataA group of conductance elements connected in seriesA group of conductance elements connected in parallelOne or more pumps connected with a series of conductance elementsA data representation of specific gas propertiesLibrariesA library is a data file containing a list of gas load or geometry reference information that is used when building asystem model.Permeation library:Out Gas library:Pipe library:O-Ring library:Archive of common permeation material dataArchive of common out gas material dataArchive of standard pipe sizesArchive of common o-ring dimensionsStudiesA study is an interactive dialog that enables rapid parametric modeling.Simple system study:Parallel conductance study:Series conductance study:A very simple representation of a vacuum system that enables rough order ofmagnitude calculationsModels parallel conductances while varying the diameter, generates aconductance graphModels series conductances while varying the diameter, generates a conductancegraphViewersA viewer provides access to a text or graphics fileText viewerGraphics viewer3.3For starters, what’s important to remember?Most people just want to do a simple pump down calculation when they get started.This is1)2)3)4)5)6)what you need to know:Open a new system model (File|Open, select “System Model”, click OK)Add at least one conductance element, such as a pipeAdd at least one pumpSet the pumping start and stop pressure (Pressure settings)Set up the vacuum vessel with volume, start and target pressureUse the Graph menu and select Pump Down Time© 2011 Professional Engineering ComputationsIntroduction3.4Models27When are the different types of models used?leftleftleftleftleftSystem model:UsePump down time, rate of rise, delivered speed, combined gas load effectsThe basic concept of a system m odel is show n below :Pump model:Used to simulate the speed of a pump as a function of inlet pressure, used insystem models© 2011 Professional Engineering Computations28VacTran 3Raw data gas load:When measured data is available from a test, that data can be entered withoutusing gas load formulas.